In a double-blind study, a proprietary product containing marshmallow root, licorice root, and elm bark (Throat Coat) was effective in providing rapid, temporary relief of sore throat pain in people with acute pharyngitis.⁹ Throat Coat was taken as a tea in the amount of 5 to 8 ounces, 4 to 6 times per day, for two to seven days.

Licorice has shown the ability to inhibit reproduction of HIV in test tubes.¹⁰ Clinical trials have shown that injections of glycyrrhizin (isolated from licorice) may have a beneficial effect on AIDS.¹¹ There is preliminary evidence that orally administered licorice also may be safe and effective for long-term treatment of HIV infection.¹² Amounts of licorice or glycyrrhizin used for treating HIV-positive people warrant monitoring by a physician, because long-term use of these substances can cause high blood pressure, potassium depletion, or other problems. Approximately 2 grams of licorice root should be taken per day in capsules or as tea. Deglycyrrhizinated licorice (DGL) will not inhibit HIV.

The mucilage of slippery elm gives it a soothing effect for coughs. Usnea also contains mucilage, which may be helpful in easing irritating coughs. There is a long tradition of using wild cherry syrups to treat coughs. Other traditional remedies to relieve coughs include bloodroot, catnip, comfrey (the above-ground parts, not the root), horehound, elecampane, mullein, lobelia, hyssop, licorice, mallow, (Malvia sylvestris),red clover, ivy leaf, pennyroyal (Hedeoma pulegioides, Mentha pulegium),onion, (Allium cepa), and plantain (Plantago lanceolata, P. major). None of these has been investigated in human trials, so their true efficacy for relieving coughs is unknown.¹³

The Chinese herb bupleurum, as part of the herbal formula sho-saiko-to, has been shown to have beneficial immune effects on white blood cells taken from people infected with HIV.¹⁴ Sho-saiko-to has also been shown to improve the efficacy of the anti-HIV drug lamivudine in the test tube.¹⁵ One preliminary study found that 7 of 13 people with HIV given sho-saiko-to had improvements in immune function.¹⁶ Double-blind trials are needed to determine whether bupleurum or sho-saiko-to might benefit people with HIV infection or AIDS. Other herbs in sho-saiko-to have also been shown to have anti-HIV activity in the test tube, most notably Asian scullcap.¹⁷ Therefore studies on sho-saiko-to cannot be taken to mean that bupleurum is the only active herb involved. The other ingredients are peony root, pinellia root, cassia bark, ginger root, jujube fruit, Asian ginseng root, Asian scullcap root, and licorice root.

Demulcents herbs may be used to treat indigestion and heartburn. These herbs seem to work by decreasing inflammation and forming a physical barrier against stomach acid or other abdominal irritants. Examples of demulcent herbs include ginger, licorice, and slippery elm.

Licorice protects the mucous membranes lining the digestive tract by increasing the production of mucin, a compound that protects against the adverse effects of stomach acid and various harmful substances.¹⁸ The extract of licorice root that is most often used by people with indigestion is known as deglycyrrhizinated licorice (DGL). Glycyrrhizin, which occurs naturally in licorice root, has cortisone-like effects and can cause high blood pressure, water retention, and other problems in some people. When the glycyrrhizin is removed to form DGL, the licorice root retains its beneficial effects against indigestion, while the risk of side effects is greatly reduced. The usual suggested amount of DGL is one or two chewable tablets (250–500 mg per tablet), chewed and swallowed 15 minutes before meals and one to two hours before bedtime.¹⁹ Although many research trials show that DGL is helpful for people with peptic ulcers, the use of DGL for heartburn and indigestion is based primarily on anecdotal information.

Many of the same herbs that are helpful for peptic ulcers may also aid people with gastritis. Licorice root, for example, has been traditionally used to soothe inflammation and injury in the stomach. Its flavonoid constituents have been found to stall the growth of H. pylori in test tube studies.²⁰ However, there have been no clinical trials using licorice to treat gastritis. To avoid potential side effects, such as increasing blood pressure and water weight gain, many physicians recommend deglycyrrhizinated licorice (DGL). This form of licorice retains its healing qualities by removing the glycyrrhizin that causes problems in some people.

Aloe vera juice has anti-inflammatory activity and been used by some doctors for people with UC. In a double-blind study of people with mildly to moderately active ulcerative colitis, supplementation with aloe resulted in a complete remission or an improvement in symptoms in 47% of cases, compared with 14% of those given a placebo (a statistically significant difference).²¹ No significant side effects were seen. The amount of aloe used was 100 ml (approximately 3.5 ounces) twice a day for four weeks. Other traditional anti-inflammatory and soothing herbs, including calendula, flaxseed, licorice, marshmallow, myrrh, and yarrow. Many of these herbs are most effective, according to clinical experience, if taken internally as well as in enema form.²² Enemas should be avoided during acute flare-ups but are useful for mild and chronic inflammation. It is best to consult with a doctor experienced with botanical medicine to learn more about herbal enemas before using them. More research needs to be done to determine the effectiveness of these herbs.

A variety of anti-inflammatory herbs historically have been recommended by doctors for people with Crohn’s disease. These include yarrow, chamomile, licorice, and aloe juice. Cathartic preparations of aloe should be avoided. No research has been conducted to validate the use of these herbs for Crohn’s disease.

Carminatives are a class of herbs commonly used for infants with colic. These herbs tend to relax intestinal spasms.

Chamomile is a carminative with long history of use as a calming herb and may be used to ease intestinal cramping in colicky infants. A soothing tea made from chamomile, vervain, licorice, fennel, and lemon balm has been shown to relieve colic more effectively than placebo.²³ In this study, approximately 1/2 cup (150 ml) of tea was given during each colic episode up to a maximum of three times per day.

Traditionally, herbs that have a soothing action on bronchioles are also used for asthma. These include marshmallow, mullein, hyssop, and licorice. Elecampane has been used traditionally to treat coughs associated with asthma.²⁴

The Japanese herbal formula known as sho-seiryu-to has been shown to reduce symptom, such as sneezing, for people with hay fever.²⁵ Sho-seiryu-to contains licorice, cassia bark, schisandra, ma huang, ginger, peony root, pinellia, and asiasarum root.

A variety of herbs with weak estrogen-like actions similar to the effects of soy have traditionally been used for women with menopausal symptoms.²⁶ These herbs include licorice, alfalfa, and red clover. In a double-blind trial, a formula containing tinctures of licorice, burdock, dong quai, wild yam, and motherwort (30 drops three times daily) was found to reduce symptoms of menopause.²⁷ No effects on hormone levels were detected in this study. In a separate double-blind trial, supplementation with dong quai (4.5 grams three times daily in capsules) had no effect on menopausal symptoms or hormone levels.²⁸ A double-blind trial using a standardized extract of subterranean clover (Trifolium subterraneum), a relative of red clover, containing 40 mg isoflavones per tablet did not impact symptoms of menopause, such as hot flashes, though it did improve function of the arteries.²⁹ An extract of red clover, providing 82 mg of isoflavones per day, also was ineffective in a 12-week double-blind study.³⁰ In another double-blind study, however, administration of 80 mg of isoflavones per day from red clover reduced the frequency of hot flashes in postmenopausal women. The benefit was noticeable after 4 weeks of treatment and became more pronounced after a total of 12 weeks.³¹

A variety of herbs with weak estrogen-like actions similar to the effects of soy have traditionally been used for women with menopausal symptoms.³² These herbs include licorice, alfalfa, and red clover. In a double-blind trial, a formula containing tinctures of licorice, burdock, dong quai, wild yam, and motherwort (30 drops three times daily) was found to reduce symptoms of menopause.³³ No effects on hormone levels were detected in this study. In a separate double-blind trial, supplementation with dong quai (4.5 grams three times daily in capsules) had no effect on menopausal symptoms or hormone levels.³⁴ A double-blind trial using a standardized extract of subterranean clover (Trifolium subterraneum), a relative of red clover, containing 40 mg isoflavones per tablet did not impact symptoms of menopause, such as hot flashes, though it did improve function of the arteries.³⁵ An extract of red clover, providing 82 mg of isoflavones per day, also was ineffective in a 12-week double-blind study.³⁶ In another double-blind study, however, administration of 80 mg of isoflavones per day from red clover reduced the frequency of hot flashes in postmenopausal women. The benefit was noticeable after 4 weeks of treatment and became more pronounced after a total of 12 weeks.³⁷

Zemaphyte, a traditional Chinese herbal preparation that includes licorice as well as nine other herbs, has been successful in treating childhood and adult eczema in double-blind trials.^38,39,40 One or two packets of the combination is mixed in hot water and taken once per day. Because one study included the same amount of licorice in both the placebo and the active medicine, it is unlikely that licorice is the main active component of Zemaphyte.⁴¹

Several Chinese herbal creams for eczema have been found to be adulterated with steroids. The authors of one study found that 8 of 11 Chinese herbal creams purchased without prescription in England contained a powerful steroid drug used to treat inflammatory skin conditions.⁴²

Licorice has been used by doctors as a topical agent for shingles and postherpetic neuralgia; however, no clinical trials support its use for this purpose. Glycyrrhizin, one of the active components of licorice, has been shown to block the replication of Varicella zoster.⁴³ Licorice gel is usually applied three or more times per day. Licorice gel is not widely available but may be obtained through a doctor who practices herbal medicine.

One case report described a man with CFS whose symptoms improved after taking 2.5 grams of licorice root daily.⁴⁴ While there have been no controlled trials to test licorice in patients with CFS, it may be worth a trial of six to eight weeks using 2 to 3 grams of licorice root daily.